Waterreus, who opened the bowling for Otago last season, took 10 wickets at an average of 18.40 but has decided to take some time off to go on her OE.
The Spark have also lost the services of Kylie Griffiths and Shannon King. Both cannot play because of work commitments.
On the positive side of the ledger, dual cricket and basketball international Suzie Bates will plug the vacancy left by Waterreus' departure.
The all-rounder is in Sydney playing club cricket and is due to return to Dunedin early next month. She is an explosive player with both bat and ball and her return will bolster the Sparks' prospects.
White Fern Sarah Tsukigawa will captain the side, which includes experienced wicketkeeper-batsman Katey Martin.
Player-coach Clare Taylor is undecided whether she will don the playing strip too often this season.
But the 43-year-old said she would fill in if there were injury concerns or a drop-off in form.
The Sparks begin their preparations with a warm-up match against Canterbury in Timaru this weekend.
Taylor said the match would serve to trial some of the young bowlers who had come into the side, with the likes of Invercargill's Jo Meyer and Oamaru's Tessa Hopkinson having an opportunity to impress.
"That's what this week is all about," Taylor said.
"It is one thing to look good in the nets but if you can't perform out in the middle then you just can't fit in."
Taylor was disappointed the Sparks do not have any games in Dunedin but was looking at the bigger picture.
"It's the Otago Sparks, isn't it. It is not just about Dunedin," she said, adding it was a good opportunity to promote the game in the regions.
The Sparks' campaign begins against Auckland at Molyneux Park in Alexandra on December 6.
Sparks
Squad
Sarah Tsukigawa (c), Suzie Bates, Kylie Crowley, Lucy Foote, Lisa Grant, Tessa Hopkinson, Abigail Kitchin, Megan Kane, Alana Kane, Katey Martin, Jo Meyer, Tanya Morrison, Ariana Te Wake.
Coach: Clare Taylor
